TRAX Multifunction transformer and substation test system
Replaces the need for multiple test sets
Perform more than 20 different electrical test functions on power transformers and other substation assets with one device
Powerful, portable and compact system
No part of the system weighs more than 32 kg, making it a truly mobile transformer and substation test system
Reduces user training and testing time
A configurable, easy-to-use interface that displays only the necessary functionality. This gives you simplicity, even when performing complex tasks
Extend the life of power transformers
Assess the condition of assets to reduce downtime and maintain reliability by detecting faults at an early stage
Manage and analyse test data
Present clear and structured reports by exporting the test data to any asset management system for further analysis
About the product
TRAX is not just a multifunctional test instrument, but many intelligent instruments in one. The software includes several apps, making it fast and easy to perform a large range of different tests. The hardware, range of cables and accessories offers unmatched flexibility, making the TRAX an efficient and time-saving system.
TRAX is packed with functionalities to make the test engineer’s task easier and quicker. For example, the 100 A true DC test current with a 50 V compliance voltage for winding resistance measurements or the 250 V AC voltage for turns ratio measurements. Also, the adaptive technique for the fastest and most efficient demagnetisation of a transformer core and the patented technique for acquiring authentic, dynamic resistance measurements on on-load tap changers to determine the real magnitude of transition resistances and transition times. TRAX also features 12 kV power factor/tan delta testing, patented temperature correction, voltage dependence detection, and narrowband dielectric frequency response (NB DFR) testing, making it a robust transformer test system.
TRAX includes Megger's market leading circuit breaker testing technology and is the only multifunctional test set on the market that offers the following tests:
- Timing test (O, C, OC, CO and OCO)
- Coil supply voltage (Station voltage)
- Pre-insertion resistance (PIR)
- Open coil current
- Breaker analysis graphs (timing, voltage, current)
TRAX offers full manual control of inputs and outputs - a unique tool for immediate troubleshooting. Routine procedures can be reproduced or modified using the manual control features to vary voltage, current, and/or frequency. TRAX is a portable metrology laboratory ideal for advanced users, research institutions, and root cause analysis specialists.
Manual control gives you access to control and operate:
- 10 generators (AC and DC; voltage and current)
- 6 measurement channels (AC and DC; voltage and current)
- Electrical formulae calculator
- Real-time oscilloscope
Technical specifications
- Input voltage
- 100 - 240 V, 50/60 Hz (±10%)
- Max output current (DC)
- 100 A (2 min), 70 A (continuous)
- Test type
- Complete transformer test systems
- Test type
- Capacitance and dissipation/power factor
Further reading and webinars
Related products
Troubleshooting
The ground loop detector must be satisfied that there is a common ground between the test instrument, the instrument’s power source, and the asset under test. If the ground loop resistance is too high, the light between the Interlock 1 key and Interlock 2 plug will light up, and the screen will display a ground loop detection (GLD) failed message. In this case, ensure that the mains ground is connected to the same ground grid as the TRAX protective conductor that connects to the test object ground.
Note: You can toggle the ground loop detector on or off for all generators except the 2 kV generator and the TDX120 accessory.
The TRAX has several different software options depending on the package and accessories that you purchased. All TRAX test sets come with manual control, turns ratio (TTR), winding resistance (WR), adaptive demagnetisation, excitation current (2 kV), and short-circuit impedance (leakage reactance). These apps should always be available. Additional apps are available if you purchased those packages, and you can unlock them with a code specific to the serial number of the TRAX. There are also certain apps that can only be operated when additional hardware is connected, for example, the tan delta/power factor app with the TDX120 high voltage unit. If you do not have the accessory or even the TRAX available, you can still create a test template in the TRAX software when using offline mode.
You can upgrade the TRAX software easily via the internet or with a USB:
Upgrading via the internet:
- Connect the TRAX to an open internet port with unlimited access, e.g., some networks limit access to hardware and devices that the IT department didn’t issue. In this case, they will need to give TRAX permission on the network. If this is not an option, then updating via USB is available.
- Select “Global Settings” from the home page and “Update.”
- The TRAX will start searching for available updates, and if/when an update is found, it will display “Update available.” Download the update.
- Start the updating process.
Upgrading via USB:
- Download the update from the link below and place it on a USB stick in the root directory.
- Insert the USB stick into one of the USB ports on the TRAX.
- From the home page, select “Global settings,” then “Updates” and “USB.”
- Download the update.
- Start the updating process.
We recommended restarting the TRAX after an upgrade.
Interlock 2 cannot be deactivated for the 2.2 kV output or when using the TDX120 accessory. You can, however, deactivate Interlock 2 for the other lower voltage and current outputs. The keyed Interlock 1 is always required.
Interpreting test results
The TRAX is a unique device that is a multifunctional solution for transformer and substation testing. With its manual control, you can program the TRAX to change inputs and outputs as well as perform mathematical functions on the measurements so that interpreting results can vary widely since multiple combinations of inputs and outputs can be applied. The TRAX also has multiple power transformer and instrument transformer apps with predefined test parameters. Hence, an interpretation of the results is almost endless or at least too large to fit in this section. Therefore, we provide analytic tips for the standard transformer tests here or a link to other dedicated products' results interpretation sections that perform the same type of test. You may find data interpretation guidelines for additional tests in Megger application notes or technical guides. A convenient data interpretation summary table is included below for your convenience.
Two of the most common tests performed on a power transformer are transformer turns ratio (TTR) and winding resistance (WR). These apps are available in the standard transformer package of the TRAX. TTR measures the cumulative turns to cumulative turns ratio between the primary and secondary, or primary and tertiary, windings. A change in TTR values can be due to shorted turns, open turns, tap changer malfunction, core problems, or incorrect or improper winding connections.
WR evaluates the transformer windings and tap changer(s). Changes in resistance values (after temperature is taken into account) are indications of shorted turns, broken strands, faulty or corroded connections between winding and bushings, or within a tap changer.
Megger's MWA instrument is explicitly dedicated to TTR and WR;
click here to see the MWA product support page for results interpretation on TTR and WR tests.
With the optional TDX 12 kV booster box, you can perform power factor (PF) or tan delta (TD) to evaluate the insulation condition of the transformer. A PF test can indicate deteriorated insulation and wet oil and paper in the transformer and bushings. With narrowband dielectric frequency response (NBDFR), you gain further insight and more confidence in your PF readings. With the high voltage source of the TDX, you can also perform a high voltage excitation current test that helps to detect winding and core problems.
The Megger DELTA4000 test instrument is a dedicated PF and TD instrument. Click here to see the DELTA4000 product support page, where you will find data interpretation guidance for both PF and excitation current.
The TRAX's standard transformer package also provides a short circuit impedance or leakage reactance app. Theoretically, a transformer's primary and secondary winding should be 100 % coupled by magnetic flux. But in reality, a transformer always has a small amount of leakage flux. The number of winding turns cut by leakage flux largely depends on a winding's position. This, in turn, influences leakage reactance. Thus, a physical or mechanical change in the windings can change leakage reactance from its benchmark value.
This test involves injecting AC current into the primary winding and measuring the voltage drop across the winding while the secondary winding is shorted. At the transformer factory, three-phase injection is used for impedance testing. Three-phase injection is not practical in the field, so current is injected into line-line winding terminals.
Two methods are typically performed in the field: a three-phase equivalent test (check nameplate impedance on the setup screen in the TRAX) and a per-phase test. The result of a three-phase equivalent test can be compared to the nameplate impedance on the transformer, assuming it is a Delta or Wye connection. Zigzag transformers require a three-phase source, so these tests are not performed for these configurations. Per-phase leakage reactance tests, meanwhile, are more sensitive to winding deformation than three-phase equivalent tests.
The difference between per-phase leakage reactance results is typically less than 2 %. A three-phase equivalent impedance result should not differ from the nameplate impedance by more than 2 to 3 %. IEEE C57.152 allows 3 % compared to the factory report, whereas CIGRE445 allows only 2 %. This percentage change is not an absolute percentage change but a change in the percentage of the actual value, e.g., if the nameplate is 5.0 % and the three-phase equivalent measurement is 5.4 %, this indicates a difference of 8 % and needs to be investigated. When comparing to the factory report, you must be on the same tap and power rating at which the factory measured the impedance. A significant change in impedance warrants your further investigation. A Sweep Frequency Response Analysis (SFRA) test is beneficial in confirming a problem in such a case.
Interpretation summary | |
---|---|
Turns Ratio Test | Measurement ±0.5 % vs. nameplate. |
Magnetic Balance | The sum of induced voltages should add up to the applied voltage. With the mid-limb excited, the extreme limbs will have 40 to 60 % induced voltage. With the extreme limbs excited, the middle limb will have 60 to 90 % induced voltage and the other extreme limb will have 10 to 40% induced voltage. |
Winding Resistance Test | Comparative analysis for three-phase between windings gives an error between 2-3 %. Each winding evaluated individually. |
Leakage Reactance | 3-phase equivalent short circuit impedance should be within 2-3 % of nameplate. |
Dynamic Resistance Measurement | Comparative analysis: Timing; Ripple; Resistance Value |
Frequency Response of Stray Losses | The analysis of FRSL results is best carried out by making comparisons with the results of earlier test made on the same transformer. Short-circuited strands reveal themselves in the data as curves that overlay at low frequencies and then start to diverge at higher frequencies. CIGRE 445 Guide for Transformer Maintenance, defines the fail criterion for the FRSL diagnostic as a difference in AC resistance between phases of greater that 15 %. |
Exciting current | Symmetrical phases within 5 %. Typical phase pattern of two similar high and one low. |
Transformers Line-frequency DF/PF at 20℃ | For transformers > 230 kV, 0.4 % For transformers < 230 kV, 0.5 % Service aged units < 1 % |
Capacitance and DF/PF | As published by IEEE C57.152, in the field, transformer insulation systems should not change by more than 5 % from the benchmark results. If the results are above 5 % and below 10 % change, an investigation needs to be conducted to determine the extent or severity of the issue. If the capacitance has changed by more than 10 %, the transformer should not be returned to service. |
Transformers 1 Hz DF/PF at 20℃ | Good < 1 % Service aged between 1 and 2 % Investigate < 2 % |